WOMS
C code chassis Medium severity

C1187 Brake Fluid Level Sensor Input Open Circuit

The OBD2 code C1187 indicates that there is an open circuit in the brake fluid level sensor input, meaning the sensor is not providing a signal to the vehicle's control module, which may suggest a fault in the sensor or...

Definition

The OBD2 code C1187 indicates that there is an open circuit in the brake fluid level sensor input, meaning the sensor is not providing a signal to the vehicle's control module, which may suggest a fault in the sensor or its wiring

Common causes

  • Faulty brake fluid level sensor
  • Damaged or corroded wiring
  • Poor electrical connections
  • Blown fuse
  • Faulty brake fluid level sensor connector
  • Low brake fluid level
  • Short circuit in the wiring harness

Common misdiagnoses

  • Faulty brake fluid level sensor
  • Wiring issues or damaged connectors
  • Brake fluid contamination
  • ABS module failure
  • Instrument cluster malfunction
  • Low brake fluid level
  • Faulty brake master cylinder

Troubleshooting steps

  1. 1. Visual Inspection

    Check Wiring and Connectors: Inspect the wiring harness and connectors leading to the brake fluid level sensor for any signs of damage, corrosion, or loose connections

  2. 2. Brake Fluid Reservoir

    Ensure that the brake fluid reservoir is properly filled and that there are no leaks

  3. 3. Test the Brake Fluid Level Sensor

    Sensor Functionality: Use a multimeter to test the brake fluid level sensor. Check for continuity and resistance according to the manufacturer’s specifications

  4. 4. Sensor Ground

    Ensure that the sensor has a proper ground connection

  5. 5. Check for Faulty Components

    Replace the Sensor: If the sensor is found to be faulty during testing, replace it with a new one

  6. 6. Inspect the Brake Fluid Reservoir

    Sometimes, the sensor is integrated into the reservoir. If the reservoir is damaged, it may need to be replaced

  7. 7. Scan for Additional Codes

    Check for Other Codes: Use an OBD-II scanner to check for any additional trouble codes that may provide more context or indicate related issues

  8. 8. Inspect the Brake System

    Brake Fluid Quality: Ensure that the brake fluid is clean and at the correct level. Contaminated or low brake fluid can affect sensor readings

  9. 9. Brake System Components

    Inspect other components of the brake system for any issues that may indirectly affect the sensor

  10. 10. Clear Codes and Test Drive

    Clear the Code: After performing repairs or replacements, clear the trouble code using an OBD-II scanner

  11. 11. Test Drive

    Take the vehicle for a test drive to see if the code reappears. Monitor the brake system for any unusual behavior

  12. 12. Professional Diagnosis

    Seek Professional Help: If you are unable to resolve the issue after following these steps, consider taking the vehicle to a qualified mechanic or dealership for further diagnosis. By following these steps, you should be able to identify and address the cause of the C1187 code effectively